Heat exchangers

ABSTRACT

A spiral heat exchanger primarily for use as an oil cooler on commercial vehicles, such exchanger comprising spiral heat exchange means defining two separate fluid paths, and a casing surrounding said means and including respective end plates, each end plate having a respective spiral seating for location of adjacent end of the heat exchange spiral. The heat exchanger may incorporate a tubular oil filter arranged axially of the heat exchange means.

[ Oct. 2, 1973 United States Patent 1 1 Poon et al. v

Primary Examiner-Manuel A. Antonakas Assistant Examiner-Theophil W. Streule, Jr A!t0rneyNorris & Batcman England v. U 8 0 Wu H. C m dm n w .m mL nd mm mm CL a e n :0 S s A N 7 221 Filed: Oct. 26, 1971 ABSTRACT Appl. N0.: 192,186

A spiral heat exchanger primarily for use as an oil 152 U.S. 165/163, 2l0/l84 commercial vchiclcs Such exchange l l prising spiral heat exchange means defining two sepading said means lnt. F28d 9/04 rate fluid paths, and a casing surroun and including respective end plates, each end plate having a respective spiral seating for location of adjacent end of the heat exchange spiral. The heat exchanger may incorporate a tubular oil filter arranged axially of the heat exchange means.

, 45 600W 1 34 600m l 5 7 H O 6] 2 5 "4 n/ 3 2 .m. ma e5 B f 3,200,948 Kasten 210/184 11 Claims, 4 Drawing Figures PATENTEDBBT 21915 sum 1 BF 2 .hv Pa.

HEAT EXCHANGERS This invention relates to a heat exchanger and more particularly to a spiral heat exchanger primarily for use on commercial vehicles as an oil cooler.

According to the invention there is provided a heat exchanger comprising spiral heat exchange means defining two separate fluid paths therethrough, a casing surrounding said means and including respective end plates, wherein each end plate is provided with a respective spiral seating for location of the adjacent end of the heat exchange spiral.

FIGS. 1 and 2 show a first embodiment of the heat exchanger of the invention which comprises a casing in the form ofa cylindrical outer wall 11 having respective end plates l2, l3 bolted to each end. The cylindrical outer wall 11 is formed with a radially extending water inlet 14 which is diametrically opposite a similar radially extending oil outlet 15. The end plate 13 has an axial water outlet 16 while the other end plate includes a centrally disposed removable cover plate 17 formed with an oil inlet 18.

A tubular oil filter 19 is located axially within the easing 10 and is biased against the water outlet end plate 13 by an axially disposed coil spring 20 one end of which bears against the adjacent end of the oil filter 19, the other end bearing against the cover plate 17. The oil filter 19 may of course be replaced by removal of the cover plate 17.

A spiral heat exchange means 21 is arranged between the oil filter 19 and the cylindrical outer wall 11 of the casing 10. This means 21 comprises a cast spiral plate 22 integral with the outer wall 11 and having U-shaped corrugations (see FIG. 1) which mate with respective spiral seatings 23 on the inside faces of each of the end plates (l2, 13) to define a waterflow path W and an oilflow path 0 which are completely separated from each other.

In use, the heatexchanger of the invention can, for example, be connected in a commercial vehicle (not shown) so that hot oil from the engine thereof is cooled by the engine water system. The heat exchanger is connected so that incoming hot oil first flows radially through the wall of the filter 19 and then around its spiral path defined by the heat exchanger plate 22 to flow out of the exchanger through the radial oil outlet 15. lncoming water from the cooling system of the vehicle enters through the radial water inlet 14 and flows around the heat exchanger plate 22 in the opposite sense to the flow of the oil and finally leaves the exchanger through the axial water outlet 16. Thus it will be appreciated that the water and oil are only divided by the heat exchange plate 22 in the spiral and therefore good heat exchange characteristics are obtained which are further enhanced by the fact that the oil and water flows are in opposite directions.

The heat transfer surface of the oil path 0 can be increased by partially filling the path with aluminum rice as indicated at 22a in FIG. 1 or any other suitable metal or material which is fused on the heat exchanging walls. The metal particles can be fused in such a way as to strengthen the heat exchanging walls to enable the exchanger to cope with high internal pressures. Alternatively, a spacing strip (not shown) may be located in the spiral water path'W to support the walls of the heat exchange plate 22. The spacing strip can be arranged in such a way as to obtain an improved flow pattern in the waterflow path W. Also, the internal volume available in the oil flow path 0 can be governed by the size of the rice or metal particles for any given cross section of the oilflow path.

An advantage accruing from a preferred embodiment of the invention is that it combines an oil cooler and an oil filter in a considerably simplified unit thus reducing costs and facilitating installation. Further advantages are also inherent in the design of the heat exchanger such as the fact that the surface area available on the waterflow path W is considerably increased compared with conventional tube stack type oil coolers. Furthermore, the constructions utilises mainly castings for the individual components thereby eliminating the undesirable processes of soldering or brazing. Units of varying thermal capacity can be produced simply by varying the length of the spiral heat exchange channels formed by the heat exchange plate 22. Also, the design of the heat exchanger of the invention is such that contamination between the two mediums, e.g., oil and water, is not possible thus greatly enhancing reliability.

FIGS. 3 and 4 show a second embodiment of the invention comprising a casing 24 in the form of a cylindrical outer wall 25 having respective end plates 26, 27 bolted to each end. The cylindrical outer wall 25 is formed integrally with a generally tubular portion 28 whose axis extends generally parallel to the axis of outer wall 25. The portion 28 connects with a respective complementary portion 29, 30 of each end plate 26, 27 to form an oil outlet 31 at one end and a water inlet 32 at the other end. The end plate 26 provided with the oil outlet 31 is formed with an axial oil inlet 33 whilst the other end plate 27 has an axial water outlet 34. The oil inlet 33 is formed in a removable cover plate 35 to enable filter changing.

A filter 36 of the tubular type is located axially within the casing 24 being biased against the water outlet end plate 27 by a coil spring 37 which is situated between the opposite end of the filter 36 and the cover plate 35.

A spiral heat exchange means 38 is arranged between the oil filter 36 and the cylindrical outer wall 25 of the casing 24. Such means 38 comprises two spaced apart generally rectangular metal sheets 39, 40 pinched or otherwise connected together along their longitudinal edges to form an envelope-like construction open at both ends. The metal sheets are wound into a spiral and have corrugations 41. Some of the corrugations 41 contact the adjacent metal sheet thus giving increased strength to the spiral. The corrugations 41 also increase the heat-exchanging surface area and can be positioned to give a desired liquid flow pattern within the spiral. A respective helical seating 42, 43 is provided in the inside surface of each end plates 26, 27 so as to locate the pinched together ends of the spiral. The spiral is connected to the oil and water inlets and outlets so as to define an oilflow path 0 and a waterflow path W which are completely separated from each other.

The oil inlet 33 is connected to a central tube 44 which is provided with spaced apart apertures 45 therein to promote an even distribution of the incoming oil across the filter 36. The central tube 44 is threaded at one end to enable the cover plate 35 to be located on its associated end plate 26 by a pair of lock nuts 46 screwed onto the tube 44.

In use, the heat exchanger above described can, for example, be connected in a commercial vehicle (not shown) so that hot oil from the engine thereof is cooled by water from the engine cooling system. The heat exchanger is connected so that incoming hot oil first flows through the apertures 45 in the central tube 44, then radially through the walls of the filter 36 and finally around its spiral path 0. defined by the metal sheets 39, 40 of the heat exchange means 38 until it leaves the exchanger through the oil outlet 31. Incoming water from the cooling system of the vehicle enters through the water inlet 32 and flows around its spiral path W in the heat exchange means 38 in the opposite sense to the flow of the oil and finally leaves the exchanger through the axial water outlet 34. It will be appreciated that thin gauge metals can be utilised for the metal sheets 39, 40 of the heat exchange means 38 which reduces production costs and gives good heat transfer characteristics between the two mediums, which characteristics are further enhanced by the fact that the oil and water flows are in opposite directions.

The corrugations 41 in the metal sheets 39, 40 of the spiral produce a very strong heat exchange unit which can withstand high liquid pressures owing to the rigidity caused by the corrugations 41 bracing adjacent walls of the spiral.

What we claim is:

l. A heat exchanger comprising a casing having an outer side wall and opposite end walls, annular heat exchange means within said casing seated at opposite ends on said end walls and surrounded by said side wall, said heat exchange means comprising means defining two separate substantially spiral passages that extend coextensively with a common heat conductive wall between them, a tubular filter in the space surrounded by said heat exchange means, means providing respective inlets and outlets for said passages in said casing walls, one of said inlets opening into said filter space which in turn is in fluid communication with an end of one of said passages.

2. A heat exchanger as claimed in claim 1, wherein said heat exchange means comprises a pair of spirally extending heat conductive walls and said body end walls are formed with spiral seatings for mounting the ends of said walls.

3. A heat exchanger as claimed in claim 2, wherein said heat exchange means comprises a plate formed with spirally extending corrugations of U-shaped crosssection, the folds of which mate with said seatings on the respective end walls.

4. A heat exchanger as claimed in claim 3, wherein said casing side wall is cylindrical with a respective one of the end walls removably secured thereon, said cylindrical wall being formed with a radial water inlet and a radial oil outlet, and one of said end walls being formed with a water outlet while the other end wall is provided with an oil inlet.

5. A heat exchanger as claimed in claim 1, wherein said filter is axially located with said casing and is biased against one of the end walls by a spring compressed between the other end wall and the adjacent end of the filter.

6. A heat exchanger as claimed in claim 1, wherein said heat exchange means comprises two spaced apart generally rectangular metal sheets connected together along their longitudinal edges and shaped to form an envelope-like hollow-plate construction open at both ends and said hollow-plate being wound into a spiral to define respectively an oil flow passage and a water flow passage through said means.

7. A heat exchanger as claimed in claim 6, wherein said casing comprises a cylindrical outer side wall having a respective one of the end walls secured to each end, said outer side wall being formed with a generally tubular portion whose axis extends generally parallel to the axis of said outer wall, said tubular portion having an oil outlet at one end and a water inlet at the other end, and one end wall being formed with an oil inlet while the other end wall is formed with a water outlet, said heat exchange means being connected to the inlets and outlets so as to form two completely separate passages through said heat exchange means.

8. A heat exchanger as claimed in claim 7, wherein said filter is axially located within said casing, and is biased against one end wall by a compression spring situated between the opposite end of the filter and a removable cover on the other end wall.

9. A heat exchanger as claimed in claim 6, wherein said metal sheets are provided with corrugations some of which contact the adjacent metal sheet to give increased strength to the spiral.

10. A heat exchanger as claimed in claim 7, wherein the oil inlet is connected to a central tube extending centrally of said filter provided with spaced apart apertures therein and positioned to promote an even distribution of the incoming oil through the filter.

11. A heat exchanger as claimed in claim 4, wherein heat transfer surface of the oil passage is increased by at least partially filling that passage with metal particles fused to the heat conductive walls. 

1. A heat exchanger comprising a casing having an outer side wall and opposite end walls, annular heat exchange means within said casing seated at opposite ends on said end walls and surrounded by said side wall, said heat exchange means comprising means defining two separate substantially spiral passages that extend coextensively with a common heat conductive wall between them, a tubular filter in the space surrounded by said heat exchange means, means providing respective inlets and outlets for said passages in said casing walls, one of said inlets opening into said filter space which in turn is in fluid communication with an end of one of said passages.
 2. A heat exchanger as claimed in claim 1, wherein said heat exchange means comprises a pair of spirally extending heat conductive walls and said body end walls are formed with spiral seatings for mounting the ends of said walls.
 3. A heat exchanger as claimed in claim 2, wherein said heat exchange means comprises a plate formed with spirally extending corrugations of U-shaped cross-section, the folds of which mate with said seatings on the respective end walls.
 4. A heat exchanger as claimed in claim 3, wherein said casing side wall is cylindrical with a respective one of the end walls removably secured thereon, said cylindrical wall being formed with a radial water inlet and a radial oil outlet, and one of said end walls being formed with a water outlet while the other end wall is provided with an oil inlet.
 5. A heat exchanger as claimed in claim 1, wherein said filter is axially located with said casing and is biased against one of the end walls by a spring compressed between the other end wall and the adjacent end of the filter.
 6. A heat exchanger as claimed in claim 1, wherein said heat exchange means comprises two spaced apart generally rectangular metal sheets connected together along their longitudinal edges and shaped to form an envelope-like hollow-plate construction open at both ends and said hollow-plate being wound into a spiral to define respectively an oil flow passage and a water flow passage through said means.
 7. A heat exchanger as claimed in claim 6, wherein said casing comprises a cylindrical outer side wall having a respective one of the end walls secured to each end, said outer side wall being formed with a generally tubular portion whose axis extends generally parallel to the axis of said outer wall, said tubular portion having an oil outlet at one end and a water inlet at the other end, and one end wall being formed with an oil inlet while the other end wall is formed with a water ouTlet, said heat exchange means being connected to the inlets and outlets so as to form two completely separate passages through said heat exchange means.
 8. A heat exchanger as claimed in claim 7, wherein said filter is axially located within said casing, and is biased against one end wall by a compression spring situated between the opposite end of the filter and a removable cover on the other end wall.
 9. A heat exchanger as claimed in claim 6, wherein said metal sheets are provided with corrugations some of which contact the adjacent metal sheet to give increased strength to the spiral.
 10. A heat exchanger as claimed in claim 7, wherein the oil inlet is connected to a central tube extending centrally of said filter provided with spaced apart apertures therein and positioned to promote an even distribution of the incoming oil through the filter.
 11. A heat exchanger as claimed in claim 4, wherein heat transfer surface of the oil passage is increased by at least partially filling that passage with metal particles fused to the heat conductive walls. 